Railway traffic controlling apparatus



April 11, 1939.

C. W. FAILOR RAILWAY TRAFFIC CONTROLLING APPARATUS Filed May 19, 1937 15Sheets-Sheet l INVENTOR Charle HIS ATTORNEY April 11, 1939.; CW.FAILOR2,154,265

RAILWAY TRAFFIC CONTROLLING APPARATUS Filed Ma 19, 1957 15 Sheets-Sheet2 INVENTOR 3 Q Cigrles 21 611701 HLS' ATTORNEY April 11, 1939. c. w.FAILOR RAILWAY TRAFFLC CONTROLLING APPARATUS Filed May 19, 193'? 15Sheets-Sheet 5 INVENTOR Charles Faz'lor.

HAS ATTORNEY April 11, 1939. c. w; FAILQR 2,154,265

RAILWAY TRAFFIC CONTROLLING APPARATUS Filed May 19, 1957 15Sheet's-Sheet 4 N *0 Q a w agfi ggm U INVENTOR 5 E v Cl z gples Fal'lor.HIS ATTORNEY I April' 11, 19 39. 6. w. FAILOR RAILWAY TRAFFICCONTROLLING APPARATUS Filed May 19, 1937 15 Shegts-Sheet 5 INVENTORCharles Fal'lor.

HIS ATTORNEY L\ r m MN m Nfl 5m 6 www E MA HQ www Mu HQ R Q NU Rn R w mm V hm R. km 3 P April 11, 1939. c w FAILOR 2,154,265

RAILWAY TRAFFIC CONTROLLING APPARATUS Filed Mgy 19, 1937 15 Sheets-Sheet6 HIS ATTORNEY April 11, 1939/ c. w; FAILOR 2,154,265

RAILWAY TRAFFIC CONTROLLING APPARATUS I Filed May 19, 1937 15Sheets-Sheet 7 INVENT OR Charle Faz'lan HIS ATTORNEY April 11, 1939.

c. w. FAILOR RAILWAY TRAFFIC CONTROLLING APPARATUS Filed May 19, 1937 isShee tS-Sheet s INVENTOR Charle HIS ATTORNEY April 11, 1939. c. w.FAILOR 2,154,265

RAILWAY TRAFFIC CONTROLLING APPARATUS Filed May 19, 1937 15 Sheets-Sheet9 INVENTOR HIS ATTORNEY Charleaz Fzz'lon 7 April 11, 1939. c. w. FAILORRAILWAY TRAFFIC CONTROLLING APPARATUS Filed May 19, 1937 15 Sheets-Sher,10

INVENTOR Charle .Fczzlor.

HIS ATTORNEY April 11, 1939. c w FAILOR I 2,154,265

RAILWAY TRAFFIC CONTROLLING APPARATUS Filed May 19, 1957 15 Sheets-Sheet11 INVENTOR CIICIPZGZZZ. Failor.

H13 ATTORNEY April 11, 1939. c. w. FAILOR RAILWAY TRAFFIC CONTROLLINGAPPARATUS Filed May 19, 1957 15 Shets-Sheet 12 INVENTOR Charles Fai Z01HIS ATTORNEY April 11, 1939. c, F LOR 2,154,265

' RAIL AY TRAFFIC CONTROLLING APPARATUS .Filed May 19, 1937 15Sheets-Sheet 13 INVENTORJ (Zha l Fal'lor.

1 3 ATTORNEY April 11, 1939.

c. w. FAILQR 2,154,265

RAILWAY TRAFFIC CONTROLLIN APPARATUS Filed May 19, 1937 15 Sheets-Sheetl4 75 E 7.5 :Uncoded;

' Energy.

INVENTOR .iaz'lor.

HIS ATTORNEY April 1939- c. w. FAILOR 2,154,265

RAILWAY TRAFFIC CONTROLLING APPARATUS Filed May 19, 1937 15 Sheets-Sheetl5 INVENTOR H15 ATTORNEY CharlesZ Fa! 10p.

BY L

Patented Apr. 11, 1939 UNITED STATES PATENT OFFICE RAILWAY TRAFFIGCONTROLLING APPARATUS Application May 19, 1937, Serial No. 143,481

22 Claims.

My invention relates to railway traflic controlling apparatus, andparticularly to automatic train control or cab signal systems of thecoded continuous inductive type. More particularly,

my present invention relates to the trackway portion of systems of thischaracter.

One feature of my invention is the provision, in systems of this type,of means for controlling the energy supplied to the sections in the rearof an occupied section in such a manner that the train control apparatuscarried on a train moving over the sections will assume the samerestrictive condition throughout more than one section in the rear of anoccupied section.

I shall describe several forms of apparatus embodying my invention, andshall then point out the novel features thereof in claims.

In the accompanying drawings, Fig. 1; Figs. 2A, and 2B, when placed endto end in the order named; and Figs. 3A and 33, when placed end to endin the order named, are diagrammatic views illustrating the trackwayapparatus for three-block, four-block, and five-block train controlsystems, respectively, and each embodying my invention. Fig. 4; Figs.5A, and 5B, when placed end to end in the order named; and Figs, 6A, 6B,and 60, when placed end to end in the order named, are diagrammaticviews illustrating trackway portions of systems similar to those shownin Figs. 1, 2A-2B, and 3A-3B, respectively, but wherein line conductorshave been substituted for certain relays, and each also embodying myinvention. Figs. 7A and 73, when placed end to end in the order named,is a diagrammatic view illustrating the system shown in Figs. 6A-6B-6Cbut wherein certain of the line conductors have been eliminated, andalso embodying my invention. Fig. 8 is a chart showing various otherWays in which the train control currents may be distributed to sectionsin the rear of an occupied section. Fig. 9 is a diagrammatic viewillustrating the trackway apparatus for supplying the train controlcurrents to sections in the rear of an occupied section as shown indiagram l of Fig. 8, and also embodying my invention.

Similar reference characters refer to similar parts in each of theseveral views.

Referring first to Fig. 1, the reference characters l and 2 designatethe track rails of a stretch of railway track along which trafficnormally moves in the direction indicated by the arrow. These rails aredivided by insulated joints 3 to form a plurality of track sections IT,2T, 3T, etc. As here shown, each section is provided with an alternatingcurrent track relay designated by the reference character TR with aprefix the same as the prefix in the reference character of theassociated track section. Each track relay is provided with a winding 4which is connected directly across the rails at one end of the sectionand with a winding 5 which is connected to a suitable source ofalternating current energy the terminals of which are designated BX andCK. Each section is provided with a transformer designated by thereference character M with -a prefix the same as the prefix of thereference character of the associated track section. E ach transformeris provided with a winding 6 connected across the rails at the other endof the section and with a winding I which, as will be explained more indetail hereinafter, is at times supplied with uncoded alternatingcurrent and at other times is supplied with coded alternating current.As here shown, each section is provided with a direct current approachrelay or control relay designated by the reference character AR with aprefix the same as the prefix of the reference character of theassociated track section. Each relay AR is controlled by a front contact8 of the associated track relay so that the relays AR will becomeenergized or deenergized according as the associated track relay isenergized or deenergized. Each section is provided with a direct currentrelay designated by the reference character H with a prefix the same asthe prefix in the reference character of the associated track section.Each relay H is controlled by a front contact I l of the associatedtrack relay as well as by a front contact I2 of the track relay for thesection next in advance. That is, each relay H will become deenergizedwhenever the associated track section or the section next in advance isoccupied. For energizing the direct current relays AR and H, eachsection is provided with a source of direct current the terminals ofwhich are designated B and C. Each section is provided with a codingrelay designated by the reference character CT with a prefix the same asthe prefix in the reference character of the associated track section.Each relay CT is provided with a contact 15, a contact I20, and acontact I which may, for example, operate respectively at '75, 120, ortimes per minute. Each coding relay is directly connected to terminalsBX and CX of the source of alternating current so that its contacts areoperating continuously.

When the control relays AR are energized so that front point of contact9 is closed, the supply circuit leading to the primary winding 1 of theassociated transformer M is supplied with uncoded energy to maintain theassociated track relay in its energized condition. When the relays ARare released so that the back point of contact 9 is closed, the supplycircuit leading to the winding I of the associated transformer M isconnected to an operating circuit which is supplied with uncoded energyor is connected to a control circuit to which is supplied coded energyof one rate or another depending upon the condition of the track relayand the relay H for the section next in advance.

As here shown, the section -IT is occupied by a train K so that relays4TB and 4H are both deenergized, With relay 4TH released, the apparatusis in condition to supply uncoded energy to section 3T whenever relay3AR becomes released. The circuit for supplying uncoded energy totransformer 3M may be traced over a path which passes from terminal BXthrough back point of contact I0 of relay 4TR, operating circuit forsection 3T, back point of contact 9 of relay 3AR, the supply circuit forsection 3T and winding I of transformer 3M to terminal CX.

The releasing of relay 4TB also releases relay 3H so that, when relayZAR becomes released, the section 2T will be supplied with coded energyinterrupted at the rate of 75 times per minute. The circuit forsupplying coded energy to winding I of transformer 2M may be traced overa path which passes from terminal BX through contact I5 of coding relay3CT, back point of contact I3 of relay 3H, control circuit for section2T, front point of contact I0 of relay 3TB, operating circuit forsection 2T, back point of contact 9 of relay ZAR, the supply circuit forsection 2T and winding 1 of transformer 2M to terminal CX.

Since the energization of relay 2H is not disturbed by the train K, thesection IT will be supplied with coded energy interrupted at the rate ofI20 times per minute when relay IAR becomes released. The circuit forsupplying section IT with coded energy interrupted at the rate of timesper minute may be traced over a path which passes from terminal BXthrough contact I20 of coding relay ZCT, front point of contact I3 ofrelay 2H, control circuit for section IT, front point of contact III ofrelay ZTR, operating circuit for section IT, back point of contact 9 ofrelay IAR, the supply circuit for section IT and winding I oftransformer IM to terminal CX,

The usual locomotive carried train control apparatus (not shown) isresponsive to coded energy only. That is, the train control apparatuswill assume a stop condition if no energy or uncoded energy is presentin the rails and will assume successively less restrictive proceedconditions according as the coded energy is interrupted at the rate of'75 or 120 times per minute. A following train, therefore, passing overthe stretch in the rear of train K will assume one of its proceedconditions in section IT because the rails of that section will besupplied with coded current interrupted at the rate of 120 times perminute. In section 2T, the train control apparatus on the followingtrain will assume a more restrictive proceed condition because the railsof section 2T will be supplied with coded current interrupted at therate of '75 times per minute, but when the following train traversessections ST or 4T, the train control apparatus will assume a stopcondition because the rails of section 3T will be supplied with uncodedenergy and no energy is present in the rails of section 4T due to theshunt of wheels and axles of train K.

Uncoded energy is supplied to the rails of the first section in the rearof an occupied section in order to provide a pickup circuit for thetrack relay of the rear section in the event that the rails of the rearsection should be shunted and then the shunt removed. Under thiscondition, energy will be supplied to the rails of the rear section overback point of contact III of the track relay for the section in advanceand back point of contact 9 of the associated approach or control relay.When the track relay becomes energized so that front point of contact 8becomes closed, the associated approach or control relay AR will, ofcourse, become energized to supply energy to the track circuit over thefront point of contact 9. In the event that the rails of the section areshunted and then the shunt removed while that section is being suppliedwith coded energy, the first impulse of the code will pick up the trackrelay so that the associated approach relay will also become picked upto restore the track circuit toits normal condition.

Referring now to Figs. 2A and 2B which illustrate a four-block system,each section is provided with a direct current polarized relaydesignated by the reference character D with a prefix the same as theprefix in the reference character of the associated track section. Eachsection is also supplied with a direct current slow releasing relaydesignated by the reference character DP with a prefix the same as theprefix in the reference character of the associated track section. Eachrelay DP is controlled by a front contact I5 of the associated relay D,that is, each relay DP will become energized or deenergized according asthe associated relay D is energized or deenergized. Each relay D iscontrolled by the associated track relay and the track relay for thesection neXt in advance as well as by the relay DP for the section nextin advance in such a manner that the winding of the relay D is energizedin the normal direction or in the reverse direction according as therelay DP for the section in advance is energized or deenergized providedthat the associated section and the section in advance are bothunoccupied. For example, the winding of relay 2D is provided with acircuit which passes over a path from terminal B of a source of currentthrough front point of contact I6 of relay 3DP, front contact I! ofrelay 3TB, front contact I8 of relay 2TB, relay 2D, front contact I9 ofwinding of relay ZTR, front contact 20 of relay 3TB, and front point ofcontact 2| of relay 3DP to terminal C of the source of current.

As here shown, the train K occupies the section 5T so that track relay5TB. is released. With the apparatus in this condition, the rails ofsection 4T will be supplied with uncoded energy over back point ofcontact I0 of relay 5TB, operating circuit for section 4T, back point ofcontact 9 of relay 4AR and the supply circuit for section 4T if section4T becomes occupied by a following train. The releasing of relay 5TBalso caused relay 4D to become released so that,

if a following train occupies section 3T, the rails I alternatingcurrent through contact 15 of'coding relay 4CT, back point of contact 22of relay 4D, control circuit for section 3T, front point of contact itof relay 4TR, operating circuit for section 3T, back point of contact 9of relay 3AR, supply circuit for section 3T, and winding 1 oftransformer 3M to terminal CX of the source of alter nating current. Theopening of front contact iii of relay 4D causes the contacts of relay4DP to be released so that the winding of relay 3D is energized in thereverse direction. The circuit for relay 3D may be traced over a pathwhich passes from terminal B of a source of current through back pointof contact l6 of relay 4DP, front point of contact 20 of relay 4TR,front contact it of relay 3TB, winding of relay 3D, front contact ill ofrelay 3TR, front contact I! of relay iTR, and back point of contact 2|of relay GDP to terminal C of the source of current. i

- Since relay 3D is energized in the reverse direction, the rails ofsection 2T will be supplied with coded energy interrupted at the rate of120 times per minute if that section becomes occupled by a followingtrain. The circuit for supplying coded energy to the rails of section 2Tmay be traced over a path which passes from terminal BX of a source ofalternating current through contact I20 of coding relay 3CT, reversepolar contact 23-Z4 of relay 3D, front point of contact 22 of relay 3D,control circuit for section 2T, front point of contact in of relayoperating circuit for section 2T, back point of contact 9 of relay 2AR,supply circuit for section ET, and winding 1 of transformer 2M toterminal CX of the source of alternating current. Relay 2D is energizedin the normal direction over the previously traced circuit for thisrelay because relay 3DP is energized; Under this condition, the rails ofsection iT will be supplied with coded energy interrupted at the rate of180 times per minute if that section becomes occupied by a followingtrain. The circuit for supplying coded energy to the rails of section ITmay be traced over a path which passes from terminal BX of a source ofalternating current through contact l8!!! of coding relay ZCT, normalpolar contact 23-25 of relay 2D, front point of contact 22 of relay 2D,control circuit for section 5T, front point of contact H] of relay 2TB,operating circuit for section 5T, back point of contact 9 of relay IAR,supply circuit for section IT, and winding 1 of transformer IM toterminal CX of the source of alternating current.

The train control apparatus carried on a following train traversing thesections in the rear of train K will, therefore, be caused to assume itsleast restrictive condition while occupying section iT because thatsection is supplied with coded energy interrupted 180 times per minute.

' When the following train enters section 2T, the

train control apparatus will be caused to assume a more restrictivecondition because the rails of section 2T will be supplied with codedenergy interrupted at the rate of 120 times per minute. When thefollowing train enters section 3T, the train control apparatus will becaused to assume a still more restrictive condition because the rails ofsection 2T will be supplied with coded current interrupted at the rateof '75 times per minute. The train control apparatus on the followingtrain will be caused to assume its stop condition in both sections 4Tand ET because uncoded energy will be supplied to the rails of section4T and no energy will be present in the rails of section 5T.

Referring now to Figs. 3A and 3B, which lllustrate a five-block traincontrol system, all apparatus is controlled in a manner similar to thatdescribed for the apparatus shown in Figs. 2A and. 2B except the controlfor the polarized relays D. Relay 2D, for example, is provided with acontrol circuit which passes over a path from terminal B of a source ofcurrent through front point of contact 2! of relay lDP, front contact 28of relay 3TB, front contact 29 of relay ZTR, winding of relay 2D, frontcontact 3!! of relay 2TH, front contact 3| of relay 3TH, and front pointof contact 32 of relay 4DP to terminal C of the source of current. Whencontacts 21 and 32 of relay 4DP are released they engage their backpoints of contact to thereby effect the supply of current of reverserelative polarity to the circuit of the winding of relay 2D. Relay 2D,therefore, will be energized in one direction or the other when sections2T and ST are both unoccupied according as the relay 4DP is energized ordeenergized, respectively. Energization of the winding of relay GDP iscontrolled by the neutral contact I5 of relay 4D, while energization ofthe winding of relay 4D is controlled by the track relays 4TB, and 5TBin such manner that the winding of relay 4D is deenergized when eithersection 4T or ET is occupied, but is energized when both of thesesections are unoccupied. It will be seen, therefore, that the relay 2Dwill be energized in the reverse direction not only when section 4T isoccupied but also when section ST is occupied and that the relay 2D willbe energized in the normal direction when sections 4T and ST are bothunoccupied. Each of the relays D is controlled in a manner similar tothat described for the relay 2D.

A train K is indicated diagrammatically in the section 6T so that relay6TB is released. Under this condition, if a following train enterssection ET, the rails of that section will be supplied with steadyenergy over a path which passes from terminal BX of a source ofalternating current through back point of contact ll! of relay B'I'R,operating circuit for section 5T, back point of contact 9 of relay EAR,supply circuit for section 5T, and winding 1 of transformer 5M toterminal CX of the source of alternating current.

The releasing of relay 6TB also causes. relay 5D to become released sothat, if a following train enters section 4T, the rails of that sectionwill be supplied with coded energy interrupted at the rate of times perminu e. The circuit for supplying coded energy to the rails of section4T may be traced over a path which passes from terminal BX of a sourceof alternating current through contact 15 of coding relay 5CT, backpoint of contact 22 of relay 5D, control circuit for section 4T, frontpoint of contact Ill of relay STR, back point of contact 9 of relay 4AR,and winding I of transformer 4M to terminal CX.

Relay 4D is energized in the reverse direction because relay GDP isreleased. The circuit for relay 4D may be traced over a path whichpasses from terminal B through back point of contact 27 of relay GDP,front contact 3! of relay 5TB, front contact 30 of relay 4TR, winding ofrelay 4D, front contact 29 of relay lTR, front contact 28 of relay 5TB,and back point of contact 32 of relay GDP to terminal C. Relay 4D beingenergized in the reverse direction will establish a circuit so that, ifa following train enters section 3T, the rails of that section will besupplied with coded energy interrupted at the rate of times per minute.The circuit for supplying coded current to the rails of section 3T may btraced over a path which passes from terminal BX of a source ofalternating current through contact I20 of relay 4CT, reverse polarcontact 23-24 of relay 4D, front point of contact 22 of relay 4D,control circuit for section 3T, 'front point of contact I0 of relay 4TR,operating circuit for section 3T, back point of contact 9 of relay 3AR,supply circuit for section 3T, and- Winding I of transformer 3M toterminal CX of the source of alternating current.

Relay 3D is energized in the reverse direction because relay 5DP isreleased. The circuit for relay 3D may be traced over a path similar tothe circuit previously traced for relay 4D. When relay 3D is energizedin the reverse direction, the rails of section 2T will also be suppliedwith coded energy interrupted at the rate of 120 times per minute ifthat section should become occupied by a following train. The circuitfor supplying coded energy to the rails of section 2T is similar to thecircuit, previously traced for supplying coded energy to the rails ofsection 3T.

The rails of section IT, if that section becomes occupied by a followingtrain, will be supplied with coded energy interrupted at the rate of 180times per minute because relay 2D is energized in the normal directionover its previously traced circuit. The circuit for supplying codedenergy to the rails of section IT may be traced over a path which passesfrom terminal BX of a source of alternating current through contact I80of coding relay 2CT, normal polar contact 23-25 of relay 2D, front pointof contact 22 of relay 2D, control circuit for section IT, front pointof contact III of relay ZTR, operating circuit for section IT, backpoint of contact 9 of relay IAR, supply circuit for section IT, andwinding 1 of transformer IM to terminal CX.

The train control apparatus on a following train traversing the sectionsin the rear of train K will assume its least restrictive condition whileoccupying section IT because the rails of that section will be suppliedwith coded energy interrupted at the rate of 180 times per minute. Asthe following train traverses sections 2T and 3T, the train controlapparatus will be caused to assume the same less restrictive conditionin both sections because the rails of these two sections will besupplied with coded energy interrupted at the rate of 120 times perminute. In section 4T the train control apparatus on the following trainwill be caused to assume a still more restrictive condition because therails of that section will be supplied with coded energy interrupted atthe rate of '75 times per minute. While a following train traversessections 5T and GT, the train control apparatus will be caused to assumeits stop condition because the rails of the former section will besupplied with uncoded energy and the rails of the latter section willnot be supplied with energy due to the shunting action of the Wheels andaxles of the train K.

Referring next to Fig. 4, the apparatus shown therein will govern thetrain control apparatus in the same manner as the system shown in Fig.1, but in the system shown in Fig. 4 line conductors have beensubstituted for the approach relays AR and the relays H.

Track relay 4TR is released because section 4T is occupied by a train Kso that uncoded energy is supplied over back points of contacts 44 and45 of relay 4TR through the supply circuit for section 3T to the primarywinding 1 of transformer 3M and thus to the rails of section 3T. Thetrain control apparatus on a following train occupying section 3T will,therefore, assume a stop condition.

If a following train enters section 2T so that uncoded energy isdisconnected from wires 31 and 38, the train control apparatus on thefollowing train will receive a restrictive proceed indication becausethe rails of section 2T will then be supplied with only coded energyinterrupted at the rate of 75 times per minute. Coded energy will besupplied to the rails of section 2T from secondary winding 4| oftransformer 3N over the control circuit for section 2T which circuitincludes wires 42 and 43 and front points of contacts 44 and 45 of trackrelay 3TB. The coded energy will be supplied to primary winding 46 oftransformer 3N over contact I5 of coding re-' lay 4CT and back point ofcontact 41 of relay The train control apparatus on a following trainoccupying section IT will be caused to assume a less restrictive proceedindication because uncoded energy will be disconnected from wires 31 and38 of section IT so that only coded energy interrupted at the rate of120 times per minute will be supplied to the rails of section IT.Primary winding 46 of transformer 2N is supplied with coded energy atthe rate of 120 times per minute over front contact I20 of coding relay3CT and front point of contact 41 of relay 3TH so that secondary windingM of transformer 2N will supply coded energy to transformer IM overwires 42 and 43 which form the control circuit of section 2T and frontpoints of contacts 44 and 45 of relay 2TB.

It will be noted that, under normal conditions,

- that is, when the sections are unoccupied, the

rails of each section are supplied with coded energy simultaneously withuncoded energy and that, when a section becomes occupied, the uncodedenergy will be disconnected and either coded energy or uncoded energywill be supplied to the rails in accordance with tramc conditions inadvance. The train control apparatus is so arranged that it will notassume a proceed condition if coded energy is supplied to the railssimultaneously with uncoded energy. That is, when uncoded energy ispresent in the rails, the train control apparatus will assume the stopcondition even though coded energy is also present.

Referring next to Figs. 5A and 5B, the apparatus shown therein willfunction in a manner similar to that described for the apparatus shownin Figs. 2A and 2B, but in the present figures line conductors have beensubstituted for relays AR, D, and DP.

The presence of the train K in section 5T causes the relay 5TB to bereleased to open the front points of its contacts 44 and 45 so that thesupply of coded energy to section 4T is disconnected.

Coded energy interrupted at the rate of 75 times per minute is suppliedto section 3T from secondary winding 49 of transformer 5P through backpoints of contacts 50 and 5| of relay 5TR, wires 52 and 53 which formthe control circuit of section 4T, and front points of contacts 44 and45 of track relay 4TR. Primary winding 54 of transformer 5P is suppliedwith coded energy by contact 15 of coding relay 5CT.

Coded energy interrupted at the rate of 120 times per minute is suppliedto section 2T by secondary winding 55 of transformer 58, wires 56 and 51of section 4T, front points of contacts 58 and 59 of relay 4TB, wires 52and 53 of section 3T which form the control (circuit for section 2T,front points of contacts 44 and 45 of relay 3TB, supply circuit forsection 2T, and transformer 2M. Primary winding 60 of transformer 5S issupplied with coded energy by a circuit which includes contact I20 ofcoding relay 5CT and back point of contact SI of relay 5TH.

The rails of section IT are supplied with coded energy interrupted atthe rate of 180 times per minute because relay 4TB, is energized.Primary winding 60 of transformer 48 is supplied with coded energy by acircuit which includes contact I30 of coding relay ACT and front pointof contact (ii of relay 4TR. Secondary winding 55 of transformer 48 is,therefore, supplying coded energy interrupted at the rate of 180 timesper minute to transformer IM over wires 56 and 51 of section 3T, frontpoints of contacts 58 and 59 of track relay 3TB, wires 52 and 53 ofsection 2T which form the control circuit for section IT, front pointsof contacts 44 and 45 of relay 2TB, supply circuit for section IT, andtransformer IM.

It follows, therefore, that if a following train moves over sections IT,2T, and ST to release the track relays associated with such sections,the opening of the front points of contacts 39 and 40 of these relayswill disconnect uncoded energy from the associated transformer M so thatthese sections will be supplied with coded energy only. Consequently,the train control apparatus on the following train will be caused toassume a proceed condition to correspond to the character of the codedcurrent supplied thereto. The train control apparatus on the followingtrain will, of course, assume a stop condition in sections 4T and 5Tbecause no energy is present in the rails of the latter section anduncoded energy is supplied to the former section over back points ofcontacts 44 and 45 of relay 5TB.

Referring now to Figs. 6A, 6B, and 6C, the apparatus shown therein willfunction in a manner similar to that described for the apparatus shownin Figs. 3A and 3B, but in the present figures line conductors have beensubstituted for relays AR, D, and DP.

The opening of front points of contacts 44 and 45 of relay 6TB by thepresence of train K in section 6T will disconnect coded energy from therails of section 5T so that the train control apparatus on a followingtrain occupying section 5T will be caused to assume a stop condition.

The rails of section 4T are supplied with coded energy interrupted atthe rate of '75 times per minute so that, when a following train enterssection 4T to open front contacts 35 and 40 of relay 4TB, the traincontrol apparatus on such following train will be caused to assume itsmost restrictive proceed condition. Primary winding 54 of transformer BPis supplied with coded energy over contact I5 of coding relay 5CT sothat secondary winding 49 of transformer 6P supplies coded energyinterrupted at the rate of 75 times per minute over back points ofcontacts 50 and 5| of relay 6TB, wires 52 and 53 of section 5T whichform the control circuit of section 4T, front points of contacts 44 and45 of relay 5TB, supply circuit for section 4T, and transformer 4M.

Since relay GTR is released, the rails of section 3T are supplied bycoded energy interrupted at the rate of 120 times per minute so that,when a following train enters section 3T, the opening of front contacts39 and 40 of relay 3TB will cause the train control apparatus on thefollowing train to assume a less restrictive proceed indication. Therails of section 3T are supplied with coded energy from secondarywinding 62 of transformer 6Q over back points of contacts 63 and 64 oftrack relay BTR, wires 65 and 66 of section 5T, front points of contacts50 and 5| of relay 5TB, wires 52 and 53 of section 4T which form thecontrol circuit for section 3T, front points of contacts 44 and 45 ofrelay 4TH, supply circuit for section 3T, and transformer 3M. Primarywinding 61 of transformer 5Q is supplied with coded energy over contactI20 of coding relay 6CT.

The rails of section 2T are also supplied with coded energy interruptedat the rate of 120 times per minute so that, when this section becomesoccupied by a following train to open contacts 39 and 40 of relay ZTR,the train control apparatus on such following train will be caused toassume the same restrictive condition as when occupying section 3T.Primary winding 60 of transformer 6S is supplied with coded current overa circuit which includes contact I20 of coding relay BCT and back pointof contact SI of relay 6TB, so that secondary winding 55 of transformer6S is'supplying coded energy over wires 56 and 51 of section 5T, frontpoints of contacts 63 and 64 of relay 5TB, wires 65 and 66 of section4T, front points of contacts 50 and 5| of relay 4TR, wires 52 and 53 ofsection 3T which form the control circuit for section 2T, front pointsof contacts 44 and 45 of relay 3TB, supply circuit for section 2T, andtransformer 2M.

The rails of section IT are supplied with coded energy interrupted atthe rate of 180 times per minute so that, when a following trainoccupies that section to disconnect uncoded energy from the rails, thetrain control apparatus will assume its normal proceed condition,Primary winding 50 of transformer 58 is supplied with coded energy by acircuit which includes contact I80 of coding relay 5CT and front pointof contact 6| of relay 5TB. so that secondary winding 55 of transformer58 is supplying energy to the rails of section IT over wires 56 and 51of section 4T, front points of contacts 63 and 64 of relay 4TB, wires 65and 66 of section 3T, front points of contacts 50 and 5| of relay 3TB,wires 52 and 53 of section 2T which form the control circuit for sectionIT, front points of contacts 44 and 45 of relay 2TB, supply circuit forsection IT, and transformer IM.

Referring now to Figs. 7A and 7B, the apparatus shown herein is similarto that shown in Figs. 6A, 6B, and 60, but in the present figures thenumber of line conductors have been reduced.

The releasing of relay BTR by the train K supplies uncoded energy overback point of contact I of relay BTR to the supply circuit leading toprimary winding II of autotransformer A so that secondary winding I2 ofautotransformer 5A will supply uncoded energy to the rails of section 5Tover back point of contact 13 of track relay 5TB when section 5T becomesoccupied by a following train.

When section 4T becomes occupied by a following train to open frontpoint of contact I3 and to close back point of contact I3 of relay 4TB,secondary winding I2 of autotransforrner 4A will be connected totransformer 4M so that the rails of the section will be supplied withcoded energy interrupted at the rate of 75 times per minute. The circuitfor supplying coded energy to primary winding II of autotransformer 4Apasses over a path from terminal BX of a source

